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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Banding when outputting QT from RedCine!

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sander kamp

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Does anybody else have this problem? I noticed in all my footage outputted from RedCine into quicktimes banding in all areas that should have smooth gradations. First I thought it was my screen since it is only a humble iMac screen but when I output a Tiff snapshot it doesn't have that problem. Also exporting from RedAlert doesn't have it. Tried every setting.

First image is from a uncompressed 10-bit quicktime output (but same thing with every codec), second one from a Tiff snapshot. It only shows up in certain areas but motion makes it much more visible. Needless to say this is a serious problem that makes all my RedCine outputs useless.
 
Like I said: when I output the same sequence with more or less the same settings from RedAlert then there is no banding issue, which leads me to believe that it is a issue with RedCine.

What I would like to know is it this is a problem everybody has? Or people with certain systems have? It is not an obvious problem if you're not aware of it, but it degrades image quality and adds noise and it is easy to think Red footage just looks like that when it can in fact look it lot better.

Can anybody confirm it is certainly not there on another system and RedCine output and RedAlert output look the same?

I have it on a iMac with Radeon HD2600 and 10.4, quicktime 7.5.5
 
Same here, 10 bit QT from 4k 16:9 scaled to HD 1920 by 1080 manifest bending in Redcine. But it has happened to me in a project shot with a zoom lenss ( I do not know exactly which ). On other projects shot either with cooke or zeiss high speed sets it happened only with extreem situations of small depth of field and the bending occured along the gradient of the outof focus areas.
I live under the asmption that it has to do with the way diffrent optics are grabed by the sensor. I assume that the RED lenses will resolve this issue complitly.
 
Sorry to say but it is extremely unlikely that this issue is caused by the lens.

As said by flameop, banding is normally caused by conversions of bitdepth. When there is not enough information in the image to make a smooth transition it will make a sudden 'jump' from one rgb value to another. The transition problem is mainly visible in out of focus areas where there are subtle shades of color and not much contrast. But it also amplifies noise and blockiness in other parts of the image which is harder to see. So it could very well be that many people have this problem but think this is normal for the RED camera while in fact it is not.
 
I was probably not clear enough, the banding is not caused by the lens but by the compression.
The image created has to do with the the lens, diffrent lenses produce diffrent types of out of focus. this difrences result, while compressed, in diffrent amount of banding.
 
Sure, you are right if you say different lenses produce different images, which can have influence on how much banding you will see.

But this problem doesn't have anything to do with compression. It's there on uncompressed 10 bit quicktimes output from RedCine and it's not there on compressed ProRes quicktimes output from RedAlert - for the same footage.
 
I CANNOT wait until other vendors release software.
Harry
 
I did some more testing but it is hard to predict when things are happening. It's definitely there but the effect varies from very subtle to quite obvious. The scary thing is that I now start seeing it in all kind of footage that I shot earlier and converted to prores in RedCine. Build 15 footage and even earlier.

The examples are 100% zoom crops from a night shot. In RedCine and RedAlert converted to prores with as much as possible default settings. In Apple Motion converted to Tiff still with 10 to 8 bit dithered conversion and finally converted to jpeg in photoshop. Long story but the idea is that both images are treated in exactly the same way.

The second pair of images I applied a curve in photoshop to make the problem more obvious - by then they were already 8 bit so you can expect banding to happen, still the quality difference is quite shocking.
 
this is the issue working with tools that are now sub par with the new quality that RED records. I'ts now time for ALL the post tools to be float point
 
isn't the difference come from CPU based calculation and GPU based? I assume in GPU process, it's giving up more complete processing when calculation becomes out of buffer. I see this kind of problem happens in audio processing between DSP based and CPU based that when the buffer is out then the phase start to get screwed up. Some companies even equalize the certain range to hide the back phase area, therefore those systems are not preffered by classic music jobs.

I did run into this banding problem but I was thinking it's because of profess, but I guess not. I have three different cards so I should check if the results were different from each other.
 
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